1. The problem statement, all variables and given/known data We are lowering two small balls into the container filled with oil. We are measuring the final velocities of these balls achieved. For the steel ball we measure the final velocity of v1 = 0.23m/s and for the aluminum ball we measure v2 = 0.06m/ s. What are the density and the viscosity of oil, if the radius's of both balls are r = 3mm; the density of steel is ρ1 = 7800 kg/m3, and the density of aluminum is ρ2 = 2700 kg/m3. Assume that the linear law of resistance applies. 2. Relevant equations ρ= m/V 3. The attempt at a solution Volume of the sphere= 4/3 πr³ 1000 kg/m³= 1 g/cm³ r= 3 mm= 0.3 cm ρ= 7800 kg/m³= 7.8 g/cm³ ρ= 2700 kg/m³= 2.7 g/cm³ V= 0.11304 cm³ ρ = m/V → m= ρV m(steal ball)= 0.88 g m(aluminum ball)= 0.31 g And this is all I managed to calculate. I know that conservation of mass and conservation of momentum apply to the density problems, but I don’t know how to apply them to find the density of oil. I really need help, please! Thank you!